A World to Explore

My Italian colleague Agostina Vertino collected this beautiful specimen from the Pleistocene of Sicily and brought it to Wooster when she visited five years ago. It is the attaching base (holdfast) of the octocoralKeratoisis peloritana (Sequenza 1864). Octocorals (Subclass Octocorallia of the Class Anthozoa) are sometimes called “soft corals” because of their organic-rich, flexible skeletons. They are distinguished by polyps with eight tentacles, each of which is pinnate (feathery). Octocorals include beautiful sea fans and sea whips that require a hard substrate for stability. This particular holdfast is on a small slab of limestone.

The genus Keratoisis is known as the “bamboo coral” because it looks jointed like stalks of the plant. I collected fragments of Pleistocene Keratoisis branches during my visit to Sicily last year.Giuseppe Seguenza (1833-1889) named the species Keratoisis peloritana. He was a Sicilian natural historian with broad interests, especially in geology. Although educated as a pharmacist, he found geology much more exciting on the volcanically active islands of the Mediterranean. He eventually became a professor of geology at the University of Messina (where the bust of him shown above resides). Italian sources say Seguenza received the famous Wollaston Medal from the Geological Society of London, but that does not appear to be true. Instead it appears that he was given “the balance of the proceeds of the Wollaston Fund” as a donation at the time the medal was awarded to Thomas Huxley (in 1876). The records of the society say that “the stipend of an Italian professor was too small to enable him to prosecute his palaeontological researches as fully as he could desire” (Woodward, 1876). Giuseppe Seguenza died in Messina at 56 years old.

Fois, E. 1990. Stratigraphy and palaeogeography of the Capo Milazzo area (NE Sicily, Italy): clues to the evolution of the southern margin of the Tyrrhenian Basin during the Neogene. Palaeogeography, Palaeoclimatology, Palaeoecology 78: 87-108.

Earlier this summer I participated on a pre-conference field trip of the International Bryozoology Association throughout Sicily. We had an excellent time and saw many wondrous things. At one stop on the western side of the Milazzo Peninsula in the northwestern part of the island we collected fossils from a fascinating foraminiferal ooze deposit known as the “Yellow Calcareous Marls” (Gelasian, Lower Pleistocene). Among the fossils in this unit were the objects pictured above. They looked like finger bones at first, but are actually the internodes (calcitic skeletal elements) of an octocoral known as “bamboo coral“. This particular species is Keratoisis melitensis (Goldfuss, 1826). I’ve never seen this group before in the fossil record. (Note, by the way, that these specimens are encrusted by foraminiferans and octocoral holdfasts. This means they rolled around on the seafloor for an extended period before burial.)Bamboo coral belongs to the octocoral group and is only a distant relative of reef-forming “hard corals” or scleractinians. They are common today in deep seas because they do not need sunlight for photosynthetic symbionts like most hard corals do. They have multiple polyps for feeding, none of which can retract back into the skeleton. That is why the surface of these internodes is so smooth and without the usual corallite holes. Above is a colony of white bamboo coral (Keratoisis flexibilis); image from Wikimedia Commons.Here we have a dried specimen of Keratoisis from the Florida Straits. You can see the white calcitic internodes of the skeleton separated from each other by the black nodes made of an organic material called gorgonin. This explains why our fossil specimens consist entirely of the isolated internodes — the chitinous parts did not survive fossilization. (Image from NOAA.)

Bamboo corals are long-lived, and it has been recently discovered that they incorporate trace elements in their skeletons as they grow, making them excellent specimens for studying changes in the chemistry and circulation of deep-sea waters. These fossils may thus someday be useful for sorting out the complex changes in the Mediterranean during the Pleistocene.

The above fossils were collected from a Lower Pleistocene silty marl exposed near the Megara archaeological site east of Augusta, Sicily, Italy. I was on that epic International Bryozoology Association field trip this summer I’ve been blogging about. The shells in this locality are very abundant with hundreds of species represented, from foraminiferans to shark teeth. I thought this little vignette of a predator and its typical prey was worth noting.

On the far right is a naticid gastropod (moon snail). These mollusks are predators who kill and consume their prey by drilling holes into their shells with a specialized radula (a kind of tooth-bearing “tongue”). Their holes are distinctively beveled, with a wider portion on the outside narrowing to a smaller inner opening. The three organisms on the left all show boreholes indicating that they were likely killed and eaten by a naticid.

Or at least that’s the traditional story. A paper came out this year (Gorzelak et al., 2013) comparing predatory drill holes in shells with holes produced by physical abrasion by experimental tumbling. The sizes, shapes and locations of these abrasion-produced holes are shockingly similar to those made by drilling predators. It looks like we must be careful which holes we assign to predation and which were produced by other means.

As I look at the three victims above, two of them (the high-spired turritellid gastropod on the far left and the bivalve second from the right) have nicely beveled holes with almost perfectly circular shapes. The gastropod shell that is second from the left, though, presents problems. First, it has two holes that completely penetrate the shell. Predators occasionally bore a shell twice, but not very often. Second the holes are more irregular in shape and don’t have a noticeable beveling. This could be a feature of the thinner shell of this gastropod not recording the usual naticid boring evidence, or it could be the result of physical abrasion and not predation. It is a difficult call but an important one to those plotting the evolution of this predator/prey system through time.

On a recent field trip to Sicily, our paleontological party visited outcrops at Cala Sant’Antonino on the western side of the Milazzo Peninsula in the northwestern part of the island. We saw there an Early Pleistocene sedimentary unit informally called the “Yellow Calcareous Marls”. With a handlens you would see a close view of the rock like the image above. It consists almost entirely of tiny hollow white spheres with occasional dark flecks. In the lab back home these little calcitic balls were revealed to be tests (skeletons) of foraminiferans known as Globorotalia inflata (d’Orbigny, 1839). This is a classic example of a biogenic sediment called foraminiferal ooze, samples of which are now in Wooster’s paleontological and sedimentological teaching collections.This is the outcrop of the “Yellow Calcareous Marls” at Cala Sant’Antonino from which the above samples were collected. The rock is very soft and powdery to the touch.

In this closer view of the rock the individual foraminiferal tests are more apparent. Near the center is one example showing the connected bulbous chambers (making it multilocular) and the slit-like aperture between them. These tests are slightly recrystallized, giving them a sugary look. The dark bits are sand-sized volcaniclastic grains derived from early eruptions of the Mount Etna complex.

These are modern examples of Globorotalia inflata. (The scale bars are 0.1 mm.) The bumpy surface texture, bulbous chambers and distinctive aperture make identification of the fossil examples fairly easy. The images were taken by Bruce Hayward.

Globorotalia inflata is a long-lived planktonic species, meaning it floats about near the top of the water column throughout the oceans. In life these single-celled organisms extend thin strands of material (pseudopodia) into the water around them to collect organic material and the occasional diatom or radiolarian for nutrition. They live in populations with billions of individuals, so under the right conditions their tests can accumulate on the seafloor in numbers so vast they form thick deposits, our foraminiferal oozes. Our particular ooze in this story formed in relatively deep (epibathyal), cool waters during one of the early glacial intervals. This foraminiferan turns out to be a critical guide to the age of the unit as well as its paleoenvironmental context.

References:

Fois, E. 1990. Stratigraphy and palaeogeography of the Capo Milazzo area (NE Sicily, Italy): clues to the evolution of the southern margin of the Tyrrhenian Basin during the Neogene. Palaeogeography, Palaeoclimatology, Palaeoecology 78: 87–108.

CATANIA, SICILY, ITALY–The IBA meeting has now ended and, as this is posted, I should be winging my way home across the Atlantic. It was a fantastic experience. This is a unique organization, of which I’m now proud to be a member of council. It is a combination of paleontologists and biologists who share a passion for the Phylum Bryozoa in all its manifestations. We had 77 oral presentations and dozens of posters spread among 80 participants, including students, academics, museum scientists, and very keen citizen scientists. The “international” component is taken very seriously: of the 80 people present, 27 countries were represented.All the sessions were held in the Palazzo delle Scienze building shown at the top of the page. We shared it with the regular student body, so it was a lively place. Directly above is the back wall of our meeting room with images of famous scientists who lived in Italy, from the Greeks to the 20th Century.Italians leave no ceiling unpainted. I’m not sure who the people are depicted above us, except that Amerigo Vespucci must be the one holding a map of the Americas. This room certainly makes you feel part of the international scientific enterprise.Here is one of our participants, Kevin Tilbrook, giving a presentation. All our communications were in English. Imagine the challenge of talking in your second or third language with someone else doing the same thing. I am continually amazed by the language skills here.My talk was on Friday morning, June 14. My first slide is shown above. My friend Paul Taylor and I examined two purported bryozoans common in the Paleozoic and showed that they were certainly not members of that phylum, despite some superficial resemblances.This is our conclusion slide. As you can see, it is relatively easy to say what something is not, but quite another to say what it is!The IBA conference dinner is always a big event. This one was among the most spectacular. We had dinner in the historical Palazzo Biscari. This is a view from the terrace towards the central Duomo complex.The ballroom is a Baroque fantasy. To complete the image, dinner was preceded by a choral performance from a Sicilian choir tucked back in the alcove. They sang many, many pieces, including some national favorites from countries represented among us.

And here is the group photo. Like many, I wasn’t ready for this shot, so I’ll be impressed if anyone can find me in here!

Our meeting was a spectacular success in terms of the science shared and learned, and the Sicilian cultural experiences. Thank you very much to organizers Antonietta Rosso and Rossana Sanfilippo from the University of Catania!

CATANIA, SICILY, ITALY–The very last field trip stop — and final event — of the International Bryozoology Association Conference was a trip to the south side of Mount Etna. We drove to a spot that had significant activity in 2000 and 2001. Several lateral craters appeared on the side of the mountain, and the lava flows buried parts of a restaurant and shop complex. They threatened to destroy the base of a cable car system, but firefighters with hoses managed to divert the flow by cooling it with water.My Belgian friend Hans De Blauwe and I decided to choose one of these smaller craters and hike to it within our allotted visit time. We picked this one in the center because of its symmetry and the flows that streamed from it. All of these features in and around this cone formed in 2001.We soon saw that our cone was the first of at least three cones descending in a row down the slope. The lava flow shows very distinct levees on its sides where the lava lapped over its banks and cooled, creating a walled channel.There are many car- and house-sized boulders of non-vesicular basalt scattered about. I assume these were thrown from the throats of explosive craters.We found this very cool lava tube, indicated first by a long walled channel that apparently represents a collapsed portion of the tunnel. A lava tube is formed when the periphery of a flow cools into hard rock and the still-fluid interior empties. We explore a beautiful ancient example on our Mojave Desert field trips.Our lava tube is open at both ends. Here Hans is crouching in the larger of the entrances.I took a flash image of the interior. You can see small “lavasicles” (cooled drips of lava) on the ceiling, along with a white crust of some sulfurous minerals.Here Hans is picking his way through the aa flow. In the lower right is another lava tube that extends back about three meters.The flowers on this volcanic slopes are very interesting. Hardy pioneers, they are. There are numerous clusters of these mounds of greenery. It appears that the plants settled on a bit of ash and then grew centripetally. The surrounding ash was eroded away, but the roots of these plants held onto their patches, eventually producing mounds as the surrounding sediment was removed.The mounds are made mostly of this spiny flowering plant. Maybe Hans will provide me with names later.These purple flowers often form in rings around the bases of the mounds.Nice white flowers on the 2001 ash layers.Somehow there are always daisies around, even in the most surprising places.Finally, here is a view from our craters toward Catania and the coast. A 2001 lava flow is directly below us. In the middle distance you can see a series of small cones, many of which were active in historical times. Catania is certainly in a volcanic hazard zone. The geologists, though, worry far more about earthquakes here than eruptions. An eruption, after all, gives you much more warning than a sudden and devastating ‘quake. Considering all this, and despite the occasional tornado and blizzard, Ohio looks like one of the safest places on Earth.

And to beautiful and much wetter Ohio I now return.

[A late addition to this post (June 23, 2013). Above is a close-up of ash erupted from Mount Etna in April 2013.]

CATANIA, SICILY, ITALY–Today we had our last field trip associated with the 2013 International Bryozoology Conference. We traveled to the east coast of Sicily at Castelluccio, which is south of Catania and north of Syracuse. The weather could not have been better. It was, as a commenter has said, “impossibly beautiful”.

The view above is of Early Pleistocene limestones resting on tholeitic basalt flows. As our guides said, in this place we could see the interplay of extensional tectonics, regional uplift, and glacially-controlled sea-level changes. The visuals were stunning. In the background you can see the east flank of Mount Etna.The limestones were of shallow-water origin and very diverse. One layer was almost completed bioturbated (biologically stirred up) by crustaceans, producing a trace fossil of connected tunnels called Thalassinoides.Fossils were abundant in some units. Here is an horizon rich in scallop shells. These shells are often preferentially preserved because they are made of hardy calcite rather than chemically unstable aragonite like most other mollusk skeletons.The interactions between the basalt flows and the calcareous sediments were fascinated. Above you see a black basaltic dike cutting vertically through the limestones. Why there are no visible baked zones is a mystery to me.In this image we have basalt above and sediments below. The pink color of the limestones tells us they were cooked by the hot lava that flowed over them.There are a variety of post-depositional geological processes operating at this outcrop. One of them is the superimposition of beachrock during sea-level highstands. Beachrock is a cemented sediment formed in the surf zone by precipitation of carbonate. This particular beachrock was plastered onto an eroded limestone cliff like stucco. You can see black basalt among the diverse clasts.Over it all rules Mount Etna, here viewed from the top of the outcrop. It was unusually smoky today, which does not show well in our photographs because of the murky haze. We headed to this behemoth for the second and last stop of our field trip.

CATANIA, SICILY, ITALY–One of the treats of many small scientific meetings, like the International Bryozoology Association conference I am attending now, is that we can have a variety of short field trips for all participants. Today we packed into two buses and spent the afternoon and evening in the city of Syracuse south of Catania.Syracuse was founded by Greek colonists (primarily Corinthians) over 2700 years ago. It was the home of Archimedes. He was famously killed there by a Roman soldier when the city was captured in 212 BCE. Cicero called Syracuse “the greatest Greek city and the most beautiful of them all”. The Syracusan tyrant Hiero I (who ruled from 478 to 466 BCE) built the outdoor theater shown at the top of this page. (Don’t call it an “amphitheater”!) Just above is a view of the ancient entrance to the theater above the seats. Greek engineers diverted a stream here to fill fountains and pools and eventually flow down to the front of the theater for refreshment and sometimes to be part of the performances. The theater is still used, so wooden seats have been fixed over much of the ancient stone.Behind the theater is this large ancient limestone quarry. You can make out a couple of pillars left in place on the quarry floor, along with characteristic vertical walls and square corners. The sturdy rock here was used to build the city and its walls.On one side of the quarry is this unusual cave called The Ear of Dionysius. It is 23 meters high and goes back about 65 meters. It has an uncanny resemblance to a human ear, hence at least one possible reason for the name. Inside it has smooth walls and a serpentine curve much like a meandering stream. The acoustics are unusual. Apparently even whispers inside can be heard at certain points above the cave’s entrance. The tyrant Dionysius is said to have placed his prisoners in there so that he could listen to their secrets (or to their tortured screams). There is considerable debate (which was repeated in our group) about whether this was all carved by quarriers or is a natural water-eroded slot canyon then modified for human use.Carl Simpson and Paul Taylor showing stylish Italian straw hats on our trip.At dinner this evening we had this wonderful view of the ancient harbor of Syracuse as the sun set and moon appeared above. Across the water on the end of the promontory is the Castello Maniace, which was originally completed as a fortification in 1240. King Ferdinand III gave this structure to none other than Admiral Horatio Nelson in 1799 for services rendered to the Kingdom of Naples. It stayed in private English hands until 1982 when it was given to the province of Catania.

I would describe the dinner, but you probably wouldn’t believe how many various Sicilian treats we had, including the inevitable octopus. It was a memorable evening in the middle of our intense conference.

CATANIA, SICILY, ITALY–This was the last day of our International Bryozoology Association pre-conference field trip through Sicily. We had an excellent time and covered an extraordinary amount of territory on this large Mediterranean island. We started our final day on the Capo Milazzo Peninsula in the northeastern portion of Sicily. The view above is looking north from the base of the with the main lighthouse on the right and bay on the left. Just peeking around the headland in the distance is one of the Aeolian Islands. We climbed down to study the rocks in the middle distance.One of the most striking units we saw was this Pliocene conglomerate at the base of a small paleobasin cut into a Paleozoic metamorphic complex. The clasts are a variety of metamorphic rocks, from high-grade schists and gneisses to low-grade greenstones. Eckart Hakansson for scale.This is a closer view of the conglomerates. The matrix is a foraminiferan-rich marl almost identical to the marl which lies above it (see the next image).This Pleistocene (Gelasian) marl above the conglomerates is almost 95% planktonic foraminiferans, or at least it looks that way with a handlens. There are some other fossils (see below) and a few sand-sized lithic fragments, but otherwise this is a foraminiferan ooze deposit.Besides the foraminiferans, the most common fossils in the Pliocene marls on the Capo Milazzo Peninsula are these stick-like objects. They are gorgonian octocoral internodes, probably from the species Keratoisis melitensis. I grabbed a handful and thereby tripled Wooster’s collection of fossil octocorals.Included in the marls are these cobbles and boulders of Miocene limestones slumped in from the slopes above. They often have large borings from lithophagid bivalves (producing Gastrochaenolites) and a smaller background boring by clionaid sponges (making Entobia).There are spectacular views from Capo Milazzo. This is looking north at the volcanic island of Stromboli. We spent a long time staring at it because every half-hour or so it spouts steam and smoke for a few seconds. I didn’t get to see an event, but there was a continual very light plume blowing from the right to the left.This is the only time I handed my camera to a colleague and asked for my picture taken. I couldn’t resist a view with Stromboli in the background. I also wanted to show off my new Italian hat. (I lost my regular and well-worn field hat somewhere along the way.)As we were leaving the peninsula, Mount Etna to the south let out a large puff of steam and gases into the murky air.Finally, a few shots from today to show a bit how our field trip worked. Above is our hotel in Milazzo, typical of the places we stayed around Sicily. Note all the little Fiat cars. In every city and town these cars were constantly buzzing by.This is a view from my seat in our bus. Our intrepid leader Antonietta Rosso from the University of Catania is speaking in the microphone. We are very grateful to her for her planning, energy and good humor. My legs here, by the way, are extending well into the aisle because they just did not fit in these tiny Italian seats.Antonietta Rosso is here giving us a field lecture before we descend down to the Capo Milazzo outcrops. The man taking photographs in the background is a keen Italian amateur who was very helpful. I wish I caught his name. He said one lifetime isn’t enough to enjoy all the wonders of this planet — and then there’s space!Just before lunch we had the requisite castle visit, this one in Milazzo. The Milazzo Castle suffered some bombing damage in World War II. The Germans and Italians used Milazzo and its port as a supply center for the Afrika Korps, and then later as a communications center for their resistance to the Allied invasion in 1943. The walls we are looking at here were built by the Spanish (Aragonese) in the 15th Century.Finally we passed by the Strait of Messina, with mainland Italy visible through the haze. This narrow body of water is extraordinarily deep and its sides continue to be uplifted by tectonic activity. These waters have wicked currents and have been known as a navigational hazard since antiquity. When we saw this strait we knew we had rounded the corner of Sicily and nearly completed our journey around the entire island.

Our last stop of the day on the IBA field trip was to a classic fossil locality on the north coast of Sicily about an hour east of Palermo. These are fine sandstones and marls preserving a diverse array of mollusks from the Pliocene, including the bivalves shown below. Over 130 bryozoan species have been recorded from this site since 1921. The most interesting features to me were the numerous sclerobionts, including shallow worm and barnacle borings and encrusting bryozoans and barnacles.From here it was a long drive to the beautiful and ancient city of Milazzo to prepare for our last day of the field trip.